17842e56b97ce677b83bdab09cda48bc2d89ac75aJust"""ttLib/sfnt.py -- low-level module to deal with the sfnt file format. 27842e56b97ce677b83bdab09cda48bc2d89ac75aJust 37842e56b97ce677b83bdab09cda48bc2d89ac75aJustDefines two public classes: 47842e56b97ce677b83bdab09cda48bc2d89ac75aJust SFNTReader 57842e56b97ce677b83bdab09cda48bc2d89ac75aJust SFNTWriter 67842e56b97ce677b83bdab09cda48bc2d89ac75aJust 77842e56b97ce677b83bdab09cda48bc2d89ac75aJust(Normally you don't have to use these classes explicitly; they are 87842e56b97ce677b83bdab09cda48bc2d89ac75aJustused automatically by ttLib.TTFont.) 97842e56b97ce677b83bdab09cda48bc2d89ac75aJust 107842e56b97ce677b83bdab09cda48bc2d89ac75aJustThe reading and writing of sfnt files is separated in two distinct 117842e56b97ce677b83bdab09cda48bc2d89ac75aJustclasses, since whenever to number of tables changes or whenever 127842e56b97ce677b83bdab09cda48bc2d89ac75aJusta table's length chages you need to rewrite the whole file anyway. 137842e56b97ce677b83bdab09cda48bc2d89ac75aJust""" 147842e56b97ce677b83bdab09cda48bc2d89ac75aJust 151ae29591efbb29492ce05378909ccf4028d7c1eeBehdad Esfahbodfrom __future__ import print_function, division, absolute_import 167ed91eca1eaa96b79eae780778e89bb9ec44c1eeBehdad Esfahbodfrom fontTools.misc.py23 import * 1730e691edd056ba22fa8970280e986747817bec3dBehdad Esfahbodfrom fontTools.misc import sstruct 1862dd7b2a0e0ab1109b56572c568ef5f582d8a0fdBehdad Esfahbodfrom fontTools.ttLib import getSearchRange 1930e691edd056ba22fa8970280e986747817bec3dBehdad Esfahbodimport struct 207842e56b97ce677b83bdab09cda48bc2d89ac75aJust 2104b3204dd168571635133d430a68175297282b1fjvr 22e388db566b9ba42669c7e353db4293cf27bc2a5bBehdad Esfahbodclass SFNTReader(object): 237842e56b97ce677b83bdab09cda48bc2d89ac75aJust 247e91e776c9d10d3b295de06ee7f665d8106306d8pabs def __init__(self, file, checkChecksums=1, fontNumber=-1): 257842e56b97ce677b83bdab09cda48bc2d89ac75aJust self.file = file 26ea9dfa9fb28966175bf2275d20aeb62c3040c86djvr self.checkChecksums = checkChecksums 2758d7416124dc0ebaa3faccb1b77dd5f7926a628aBehdad Esfahbod 2858d7416124dc0ebaa3faccb1b77dd5f7926a628aBehdad Esfahbod self.flavor = None 2958d7416124dc0ebaa3faccb1b77dd5f7926a628aBehdad Esfahbod self.flavorData = None 3058d7416124dc0ebaa3faccb1b77dd5f7926a628aBehdad Esfahbod self.DirectoryEntry = SFNTDirectoryEntry 3158d7416124dc0ebaa3faccb1b77dd5f7926a628aBehdad Esfahbod self.sfntVersion = self.file.read(4) 3258d7416124dc0ebaa3faccb1b77dd5f7926a628aBehdad Esfahbod self.file.seek(0) 33ac4672e4510a79a56c4983ad28b42724c30ea9d1Behdad Esfahbod if self.sfntVersion == b"ttcf": 3458d7416124dc0ebaa3faccb1b77dd5f7926a628aBehdad Esfahbod sstruct.unpack(ttcHeaderFormat, self.file.read(ttcHeaderSize), self) 357e91e776c9d10d3b295de06ee7f665d8106306d8pabs assert self.Version == 0x00010000 or self.Version == 0x00020000, "unrecognized TTC version 0x%08x" % self.Version 367e91e776c9d10d3b295de06ee7f665d8106306d8pabs if not 0 <= fontNumber < self.numFonts: 377e91e776c9d10d3b295de06ee7f665d8106306d8pabs from fontTools import ttLib 38cd5aad92f23737ff93a110d5c73d624658a28da8Behdad Esfahbod raise ttLib.TTLibError("specify a font number between 0 and %d (inclusive)" % (self.numFonts - 1)) 397e91e776c9d10d3b295de06ee7f665d8106306d8pabs offsetTable = struct.unpack(">%dL" % self.numFonts, self.file.read(self.numFonts * 4)) 407e91e776c9d10d3b295de06ee7f665d8106306d8pabs if self.Version == 0x00020000: 417e91e776c9d10d3b295de06ee7f665d8106306d8pabs pass # ignoring version 2.0 signatures 427e91e776c9d10d3b295de06ee7f665d8106306d8pabs self.file.seek(offsetTable[fontNumber]) 4358d7416124dc0ebaa3faccb1b77dd5f7926a628aBehdad Esfahbod sstruct.unpack(sfntDirectoryFormat, self.file.read(sfntDirectorySize), self) 44ac4672e4510a79a56c4983ad28b42724c30ea9d1Behdad Esfahbod elif self.sfntVersion == b"wOFF": 4558d7416124dc0ebaa3faccb1b77dd5f7926a628aBehdad Esfahbod self.flavor = "woff" 4658d7416124dc0ebaa3faccb1b77dd5f7926a628aBehdad Esfahbod self.DirectoryEntry = WOFFDirectoryEntry 4758d7416124dc0ebaa3faccb1b77dd5f7926a628aBehdad Esfahbod sstruct.unpack(woffDirectoryFormat, self.file.read(woffDirectorySize), self) 4858d7416124dc0ebaa3faccb1b77dd5f7926a628aBehdad Esfahbod else: 4958d7416124dc0ebaa3faccb1b77dd5f7926a628aBehdad Esfahbod sstruct.unpack(sfntDirectoryFormat, self.file.read(sfntDirectorySize), self) 50ac4672e4510a79a56c4983ad28b42724c30ea9d1Behdad Esfahbod self.sfntVersion = Tag(self.sfntVersion) 5158d7416124dc0ebaa3faccb1b77dd5f7926a628aBehdad Esfahbod 52ac4672e4510a79a56c4983ad28b42724c30ea9d1Behdad Esfahbod if self.sfntVersion not in ("\x00\x01\x00\x00", "OTTO", "true"): 537842e56b97ce677b83bdab09cda48bc2d89ac75aJust from fontTools import ttLib 54cd5aad92f23737ff93a110d5c73d624658a28da8Behdad Esfahbod raise ttLib.TTLibError("Not a TrueType or OpenType font (bad sfntVersion)") 557842e56b97ce677b83bdab09cda48bc2d89ac75aJust self.tables = {} 567842e56b97ce677b83bdab09cda48bc2d89ac75aJust for i in range(self.numTables): 5758d7416124dc0ebaa3faccb1b77dd5f7926a628aBehdad Esfahbod entry = self.DirectoryEntry() 58ea9dfa9fb28966175bf2275d20aeb62c3040c86djvr entry.fromFile(self.file) 596338375bd8b6d8a6888972c3cabc9a30431c152fBehdad Esfahbod self.tables[Tag(entry.tag)] = entry 6058d7416124dc0ebaa3faccb1b77dd5f7926a628aBehdad Esfahbod 6158d7416124dc0ebaa3faccb1b77dd5f7926a628aBehdad Esfahbod # Load flavor data if any 6258d7416124dc0ebaa3faccb1b77dd5f7926a628aBehdad Esfahbod if self.flavor == "woff": 6358d7416124dc0ebaa3faccb1b77dd5f7926a628aBehdad Esfahbod self.flavorData = WOFFFlavorData(self) 6458d7416124dc0ebaa3faccb1b77dd5f7926a628aBehdad Esfahbod 657842e56b97ce677b83bdab09cda48bc2d89ac75aJust def has_key(self, tag): 66bc5e1cb195c0bfa1c8e7507326d5a9ad05aecb4bBehdad Esfahbod return tag in self.tables 67bc5e1cb195c0bfa1c8e7507326d5a9ad05aecb4bBehdad Esfahbod 68bc5e1cb195c0bfa1c8e7507326d5a9ad05aecb4bBehdad Esfahbod __contains__ = has_key 697842e56b97ce677b83bdab09cda48bc2d89ac75aJust 707842e56b97ce677b83bdab09cda48bc2d89ac75aJust def keys(self): 717842e56b97ce677b83bdab09cda48bc2d89ac75aJust return self.tables.keys() 727842e56b97ce677b83bdab09cda48bc2d89ac75aJust 737842e56b97ce677b83bdab09cda48bc2d89ac75aJust def __getitem__(self, tag): 747842e56b97ce677b83bdab09cda48bc2d89ac75aJust """Fetch the raw table data.""" 75ac4672e4510a79a56c4983ad28b42724c30ea9d1Behdad Esfahbod entry = self.tables[Tag(tag)] 7658d7416124dc0ebaa3faccb1b77dd5f7926a628aBehdad Esfahbod data = entry.loadData (self.file) 77ea9dfa9fb28966175bf2275d20aeb62c3040c86djvr if self.checkChecksums: 787842e56b97ce677b83bdab09cda48bc2d89ac75aJust if tag == 'head': 797842e56b97ce677b83bdab09cda48bc2d89ac75aJust # Beh: we have to special-case the 'head' table. 80821572c9a92d338a7ecbb4261c08ce378eb5434dBehdad Esfahbod checksum = calcChecksum(data[:8] + b'\0\0\0\0' + data[12:]) 817842e56b97ce677b83bdab09cda48bc2d89ac75aJust else: 82ea9dfa9fb28966175bf2275d20aeb62c3040c86djvr checksum = calcChecksum(data) 83ea9dfa9fb28966175bf2275d20aeb62c3040c86djvr if self.checkChecksums > 1: 847842e56b97ce677b83bdab09cda48bc2d89ac75aJust # Be obnoxious, and barf when it's wrong 857842e56b97ce677b83bdab09cda48bc2d89ac75aJust assert checksum == entry.checksum, "bad checksum for '%s' table" % tag 86180ace6a5ff1399ec53bc696e8bef7cce6eef39aBehdad Esfahbod elif checksum != entry.checkSum: 877842e56b97ce677b83bdab09cda48bc2d89ac75aJust # Be friendly, and just print a warning. 883ec6a258238b6068e4eef3fe579f1f5c0a06bbbaBehdad Esfahbod print("bad checksum for '%s' table" % tag) 897842e56b97ce677b83bdab09cda48bc2d89ac75aJust return data 907842e56b97ce677b83bdab09cda48bc2d89ac75aJust 91f70746325687393330f7a765814a0fe78f11f847jvr def __delitem__(self, tag): 92ac4672e4510a79a56c4983ad28b42724c30ea9d1Behdad Esfahbod del self.tables[Tag(tag)] 93f70746325687393330f7a765814a0fe78f11f847jvr 947842e56b97ce677b83bdab09cda48bc2d89ac75aJust def close(self): 957842e56b97ce677b83bdab09cda48bc2d89ac75aJust self.file.close() 967842e56b97ce677b83bdab09cda48bc2d89ac75aJust 977842e56b97ce677b83bdab09cda48bc2d89ac75aJust 98e388db566b9ba42669c7e353db4293cf27bc2a5bBehdad Esfahbodclass SFNTWriter(object): 997842e56b97ce677b83bdab09cda48bc2d89ac75aJust 100b0dc6dfc8baf01db94782fccc2e734a281b9ba12Behdad Esfahbod def __init__(self, file, numTables, sfntVersion="\000\001\000\000", 101b0dc6dfc8baf01db94782fccc2e734a281b9ba12Behdad Esfahbod flavor=None, flavorData=None): 1027842e56b97ce677b83bdab09cda48bc2d89ac75aJust self.file = file 1037842e56b97ce677b83bdab09cda48bc2d89ac75aJust self.numTables = numTables 104ac4672e4510a79a56c4983ad28b42724c30ea9d1Behdad Esfahbod self.sfntVersion = Tag(sfntVersion) 105b0dc6dfc8baf01db94782fccc2e734a281b9ba12Behdad Esfahbod self.flavor = flavor 106b0dc6dfc8baf01db94782fccc2e734a281b9ba12Behdad Esfahbod self.flavorData = flavorData 107b0dc6dfc8baf01db94782fccc2e734a281b9ba12Behdad Esfahbod 108b0dc6dfc8baf01db94782fccc2e734a281b9ba12Behdad Esfahbod if self.flavor == "woff": 109b0dc6dfc8baf01db94782fccc2e734a281b9ba12Behdad Esfahbod self.directoryFormat = woffDirectoryFormat 110b0dc6dfc8baf01db94782fccc2e734a281b9ba12Behdad Esfahbod self.directorySize = woffDirectorySize 111b0dc6dfc8baf01db94782fccc2e734a281b9ba12Behdad Esfahbod self.DirectoryEntry = WOFFDirectoryEntry 112b0dc6dfc8baf01db94782fccc2e734a281b9ba12Behdad Esfahbod 113b0dc6dfc8baf01db94782fccc2e734a281b9ba12Behdad Esfahbod self.signature = "wOFF" 114b0dc6dfc8baf01db94782fccc2e734a281b9ba12Behdad Esfahbod else: 115b0dc6dfc8baf01db94782fccc2e734a281b9ba12Behdad Esfahbod assert not self.flavor, "Unknown flavor '%s'" % self.flavor 116b0dc6dfc8baf01db94782fccc2e734a281b9ba12Behdad Esfahbod self.directoryFormat = sfntDirectoryFormat 117b0dc6dfc8baf01db94782fccc2e734a281b9ba12Behdad Esfahbod self.directorySize = sfntDirectorySize 118b0dc6dfc8baf01db94782fccc2e734a281b9ba12Behdad Esfahbod self.DirectoryEntry = SFNTDirectoryEntry 119b0dc6dfc8baf01db94782fccc2e734a281b9ba12Behdad Esfahbod 12062dd7b2a0e0ab1109b56572c568ef5f582d8a0fdBehdad Esfahbod self.searchRange, self.entrySelector, self.rangeShift = getSearchRange(numTables, 16) 121b0dc6dfc8baf01db94782fccc2e734a281b9ba12Behdad Esfahbod 122b0dc6dfc8baf01db94782fccc2e734a281b9ba12Behdad Esfahbod self.nextTableOffset = self.directorySize + numTables * self.DirectoryEntry.formatSize 1237842e56b97ce677b83bdab09cda48bc2d89ac75aJust # clear out directory area 1247842e56b97ce677b83bdab09cda48bc2d89ac75aJust self.file.seek(self.nextTableOffset) 125b0dc6dfc8baf01db94782fccc2e734a281b9ba12Behdad Esfahbod # make sure we're actually where we want to be. (old cStringIO bug) 126821572c9a92d338a7ecbb4261c08ce378eb5434dBehdad Esfahbod self.file.write(b'\0' * (self.nextTableOffset - self.file.tell())) 1277842e56b97ce677b83bdab09cda48bc2d89ac75aJust self.tables = {} 1287842e56b97ce677b83bdab09cda48bc2d89ac75aJust 1297842e56b97ce677b83bdab09cda48bc2d89ac75aJust def __setitem__(self, tag, data): 1307842e56b97ce677b83bdab09cda48bc2d89ac75aJust """Write raw table data to disk.""" 131b0dc6dfc8baf01db94782fccc2e734a281b9ba12Behdad Esfahbod reuse = False 132bc5e1cb195c0bfa1c8e7507326d5a9ad05aecb4bBehdad Esfahbod if tag in self.tables: 1337842e56b97ce677b83bdab09cda48bc2d89ac75aJust # We've written this table to file before. If the length 13404b3204dd168571635133d430a68175297282b1fjvr # of the data is still the same, we allow overwriting it. 1357842e56b97ce677b83bdab09cda48bc2d89ac75aJust entry = self.tables[tag] 136b0dc6dfc8baf01db94782fccc2e734a281b9ba12Behdad Esfahbod assert not hasattr(entry.__class__, 'encodeData') 137180ace6a5ff1399ec53bc696e8bef7cce6eef39aBehdad Esfahbod if len(data) != entry.length: 1387842e56b97ce677b83bdab09cda48bc2d89ac75aJust from fontTools import ttLib 139cd5aad92f23737ff93a110d5c73d624658a28da8Behdad Esfahbod raise ttLib.TTLibError("cannot rewrite '%s' table: length does not match directory entry" % tag) 140b0dc6dfc8baf01db94782fccc2e734a281b9ba12Behdad Esfahbod reuse = True 1417842e56b97ce677b83bdab09cda48bc2d89ac75aJust else: 142b0dc6dfc8baf01db94782fccc2e734a281b9ba12Behdad Esfahbod entry = self.DirectoryEntry() 1437842e56b97ce677b83bdab09cda48bc2d89ac75aJust entry.tag = tag 144b0dc6dfc8baf01db94782fccc2e734a281b9ba12Behdad Esfahbod 145b0dc6dfc8baf01db94782fccc2e734a281b9ba12Behdad Esfahbod if tag == 'head': 146821572c9a92d338a7ecbb4261c08ce378eb5434dBehdad Esfahbod entry.checkSum = calcChecksum(data[:8] + b'\0\0\0\0' + data[12:]) 147b0dc6dfc8baf01db94782fccc2e734a281b9ba12Behdad Esfahbod self.headTable = data 148b0dc6dfc8baf01db94782fccc2e734a281b9ba12Behdad Esfahbod entry.uncompressed = True 149b0dc6dfc8baf01db94782fccc2e734a281b9ba12Behdad Esfahbod else: 150b0dc6dfc8baf01db94782fccc2e734a281b9ba12Behdad Esfahbod entry.checkSum = calcChecksum(data) 151b0dc6dfc8baf01db94782fccc2e734a281b9ba12Behdad Esfahbod 152b0dc6dfc8baf01db94782fccc2e734a281b9ba12Behdad Esfahbod entry.offset = self.nextTableOffset 153b0dc6dfc8baf01db94782fccc2e734a281b9ba12Behdad Esfahbod entry.saveData (self.file, data) 154b0dc6dfc8baf01db94782fccc2e734a281b9ba12Behdad Esfahbod 155b0dc6dfc8baf01db94782fccc2e734a281b9ba12Behdad Esfahbod if not reuse: 156b0dc6dfc8baf01db94782fccc2e734a281b9ba12Behdad Esfahbod self.nextTableOffset = self.nextTableOffset + ((entry.length + 3) & ~3) 157b0dc6dfc8baf01db94782fccc2e734a281b9ba12Behdad Esfahbod 158c63ac64007caf769f1e6a267403280264d4ae7bdjvr # Add NUL bytes to pad the table data to a 4-byte boundary. 159c63ac64007caf769f1e6a267403280264d4ae7bdjvr # Don't depend on f.seek() as we need to add the padding even if no 160c63ac64007caf769f1e6a267403280264d4ae7bdjvr # subsequent write follows (seek is lazy), ie. after the final table 161c63ac64007caf769f1e6a267403280264d4ae7bdjvr # in the font. 162821572c9a92d338a7ecbb4261c08ce378eb5434dBehdad Esfahbod self.file.write(b'\0' * (self.nextTableOffset - self.file.tell())) 163c63ac64007caf769f1e6a267403280264d4ae7bdjvr assert self.nextTableOffset == self.file.tell() 1647842e56b97ce677b83bdab09cda48bc2d89ac75aJust 1657842e56b97ce677b83bdab09cda48bc2d89ac75aJust self.tables[tag] = entry 1667842e56b97ce677b83bdab09cda48bc2d89ac75aJust 16728ae1962292b66ad67117aef2a99d5735a70b779jvr def close(self): 1687842e56b97ce677b83bdab09cda48bc2d89ac75aJust """All tables must have been written to disk. Now write the 1697842e56b97ce677b83bdab09cda48bc2d89ac75aJust directory. 1707842e56b97ce677b83bdab09cda48bc2d89ac75aJust """ 171ac1b4359467ca3deab03186a15eae1d55eb35567Behdad Esfahbod tables = sorted(self.tables.items()) 172180ace6a5ff1399ec53bc696e8bef7cce6eef39aBehdad Esfahbod if len(tables) != self.numTables: 1737842e56b97ce677b83bdab09cda48bc2d89ac75aJust from fontTools import ttLib 174cd5aad92f23737ff93a110d5c73d624658a28da8Behdad Esfahbod raise ttLib.TTLibError("wrong number of tables; expected %d, found %d" % (self.numTables, len(tables))) 175b0dc6dfc8baf01db94782fccc2e734a281b9ba12Behdad Esfahbod 176b0dc6dfc8baf01db94782fccc2e734a281b9ba12Behdad Esfahbod if self.flavor == "woff": 177ac4672e4510a79a56c4983ad28b42724c30ea9d1Behdad Esfahbod self.signature = b"wOFF" 178b0dc6dfc8baf01db94782fccc2e734a281b9ba12Behdad Esfahbod self.reserved = 0 179b0dc6dfc8baf01db94782fccc2e734a281b9ba12Behdad Esfahbod 180b0dc6dfc8baf01db94782fccc2e734a281b9ba12Behdad Esfahbod self.totalSfntSize = 12 181b0dc6dfc8baf01db94782fccc2e734a281b9ba12Behdad Esfahbod self.totalSfntSize += 16 * len(tables) 182b0dc6dfc8baf01db94782fccc2e734a281b9ba12Behdad Esfahbod for tag, entry in tables: 183b0dc6dfc8baf01db94782fccc2e734a281b9ba12Behdad Esfahbod self.totalSfntSize += (entry.origLength + 3) & ~3 184b0dc6dfc8baf01db94782fccc2e734a281b9ba12Behdad Esfahbod 185b0dc6dfc8baf01db94782fccc2e734a281b9ba12Behdad Esfahbod data = self.flavorData if self.flavorData else WOFFFlavorData() 1869e6ef94b5554c5b7dda2de9c863c11ed4b996b7aBehdad Esfahbod if data.majorVersion is not None and data.minorVersion is not None: 187b0dc6dfc8baf01db94782fccc2e734a281b9ba12Behdad Esfahbod self.majorVersion = data.majorVersion 188b0dc6dfc8baf01db94782fccc2e734a281b9ba12Behdad Esfahbod self.minorVersion = data.minorVersion 189b0dc6dfc8baf01db94782fccc2e734a281b9ba12Behdad Esfahbod else: 190b0dc6dfc8baf01db94782fccc2e734a281b9ba12Behdad Esfahbod if hasattr(self, 'headTable'): 191b0dc6dfc8baf01db94782fccc2e734a281b9ba12Behdad Esfahbod self.majorVersion, self.minorVersion = struct.unpack(">HH", self.headTable[4:8]) 192b0dc6dfc8baf01db94782fccc2e734a281b9ba12Behdad Esfahbod else: 193b0dc6dfc8baf01db94782fccc2e734a281b9ba12Behdad Esfahbod self.majorVersion = self.minorVersion = 0 194b0dc6dfc8baf01db94782fccc2e734a281b9ba12Behdad Esfahbod if data.metaData: 195b0dc6dfc8baf01db94782fccc2e734a281b9ba12Behdad Esfahbod self.metaOrigLength = len(data.metaData) 196b0dc6dfc8baf01db94782fccc2e734a281b9ba12Behdad Esfahbod self.file.seek(0,2) 197b0dc6dfc8baf01db94782fccc2e734a281b9ba12Behdad Esfahbod self.metaOffset = self.file.tell() 198153ec402094adbea673e914385b87f1d99191d0bBehdad Esfahbod import zlib 199b0dc6dfc8baf01db94782fccc2e734a281b9ba12Behdad Esfahbod compressedMetaData = zlib.compress(data.metaData) 200b0dc6dfc8baf01db94782fccc2e734a281b9ba12Behdad Esfahbod self.metaLength = len(compressedMetaData) 201b0dc6dfc8baf01db94782fccc2e734a281b9ba12Behdad Esfahbod self.file.write(compressedMetaData) 202b0dc6dfc8baf01db94782fccc2e734a281b9ba12Behdad Esfahbod else: 203b0dc6dfc8baf01db94782fccc2e734a281b9ba12Behdad Esfahbod self.metaOffset = self.metaLength = self.metaOrigLength = 0 204b0dc6dfc8baf01db94782fccc2e734a281b9ba12Behdad Esfahbod if data.privData: 205b0dc6dfc8baf01db94782fccc2e734a281b9ba12Behdad Esfahbod self.file.seek(0,2) 206b0dc6dfc8baf01db94782fccc2e734a281b9ba12Behdad Esfahbod off = self.file.tell() 207b0dc6dfc8baf01db94782fccc2e734a281b9ba12Behdad Esfahbod paddedOff = (off + 3) & ~3 208b0dc6dfc8baf01db94782fccc2e734a281b9ba12Behdad Esfahbod self.file.write('\0' * (paddedOff - off)) 209b0dc6dfc8baf01db94782fccc2e734a281b9ba12Behdad Esfahbod self.privOffset = self.file.tell() 210b0dc6dfc8baf01db94782fccc2e734a281b9ba12Behdad Esfahbod self.privLength = len(data.privData) 211b0dc6dfc8baf01db94782fccc2e734a281b9ba12Behdad Esfahbod self.file.write(data.privData) 212b0dc6dfc8baf01db94782fccc2e734a281b9ba12Behdad Esfahbod else: 213b0dc6dfc8baf01db94782fccc2e734a281b9ba12Behdad Esfahbod self.privOffset = self.privLength = 0 214b0dc6dfc8baf01db94782fccc2e734a281b9ba12Behdad Esfahbod 215b0dc6dfc8baf01db94782fccc2e734a281b9ba12Behdad Esfahbod self.file.seek(0,2) 216b0dc6dfc8baf01db94782fccc2e734a281b9ba12Behdad Esfahbod self.length = self.file.tell() 217b0dc6dfc8baf01db94782fccc2e734a281b9ba12Behdad Esfahbod 218b0dc6dfc8baf01db94782fccc2e734a281b9ba12Behdad Esfahbod else: 219b0dc6dfc8baf01db94782fccc2e734a281b9ba12Behdad Esfahbod assert not self.flavor, "Unknown flavor '%s'" % self.flavor 220b0dc6dfc8baf01db94782fccc2e734a281b9ba12Behdad Esfahbod pass 2217842e56b97ce677b83bdab09cda48bc2d89ac75aJust 222b0dc6dfc8baf01db94782fccc2e734a281b9ba12Behdad Esfahbod directory = sstruct.pack(self.directoryFormat, self) 2237842e56b97ce677b83bdab09cda48bc2d89ac75aJust 224b0dc6dfc8baf01db94782fccc2e734a281b9ba12Behdad Esfahbod self.file.seek(self.directorySize) 225f509c0f0707a85184525243dfb6efeba043dc793jvr seenHead = 0 2267842e56b97ce677b83bdab09cda48bc2d89ac75aJust for tag, entry in tables: 227f509c0f0707a85184525243dfb6efeba043dc793jvr if tag == "head": 228f509c0f0707a85184525243dfb6efeba043dc793jvr seenHead = 1 229ea9dfa9fb28966175bf2275d20aeb62c3040c86djvr directory = directory + entry.toString() 230f509c0f0707a85184525243dfb6efeba043dc793jvr if seenHead: 23191bca4244286fb519c93fe92329da96b0e6f32eejvr self.writeMasterChecksum(directory) 2327842e56b97ce677b83bdab09cda48bc2d89ac75aJust self.file.seek(0) 2337842e56b97ce677b83bdab09cda48bc2d89ac75aJust self.file.write(directory) 23491bca4244286fb519c93fe92329da96b0e6f32eejvr 23591bca4244286fb519c93fe92329da96b0e6f32eejvr def _calcMasterChecksum(self, directory): 2367842e56b97ce677b83bdab09cda48bc2d89ac75aJust # calculate checkSumAdjustment 237c2297cd41d6c00b95f857b65bc9fd4b57559ac5eBehdad Esfahbod tags = list(self.tables.keys()) 23891bca4244286fb519c93fe92329da96b0e6f32eejvr checksums = [] 2397842e56b97ce677b83bdab09cda48bc2d89ac75aJust for i in range(len(tags)): 24091bca4244286fb519c93fe92329da96b0e6f32eejvr checksums.append(self.tables[tags[i]].checkSum) 24191bca4244286fb519c93fe92329da96b0e6f32eejvr 242b0dc6dfc8baf01db94782fccc2e734a281b9ba12Behdad Esfahbod # TODO(behdad) I'm fairly sure the checksum for woff is not working correctly. 243b0dc6dfc8baf01db94782fccc2e734a281b9ba12Behdad Esfahbod # Haven't debugged. 244b0dc6dfc8baf01db94782fccc2e734a281b9ba12Behdad Esfahbod if self.DirectoryEntry != SFNTDirectoryEntry: 245b0dc6dfc8baf01db94782fccc2e734a281b9ba12Behdad Esfahbod # Create a SFNT directory for checksum calculation purposes 24662dd7b2a0e0ab1109b56572c568ef5f582d8a0fdBehdad Esfahbod self.searchRange, self.entrySelector, self.rangeShift = getSearchRange(self.numTables, 16) 247b0dc6dfc8baf01db94782fccc2e734a281b9ba12Behdad Esfahbod directory = sstruct.pack(sfntDirectoryFormat, self) 248ac1b4359467ca3deab03186a15eae1d55eb35567Behdad Esfahbod tables = sorted(self.tables.items()) 249b0dc6dfc8baf01db94782fccc2e734a281b9ba12Behdad Esfahbod for tag, entry in tables: 250b0dc6dfc8baf01db94782fccc2e734a281b9ba12Behdad Esfahbod sfntEntry = SFNTDirectoryEntry() 251b0dc6dfc8baf01db94782fccc2e734a281b9ba12Behdad Esfahbod for item in ['tag', 'checkSum', 'offset', 'length']: 252b0dc6dfc8baf01db94782fccc2e734a281b9ba12Behdad Esfahbod setattr(sfntEntry, item, getattr(entry, item)) 253b0dc6dfc8baf01db94782fccc2e734a281b9ba12Behdad Esfahbod directory = directory + sfntEntry.toString() 254b0dc6dfc8baf01db94782fccc2e734a281b9ba12Behdad Esfahbod 2557842e56b97ce677b83bdab09cda48bc2d89ac75aJust directory_end = sfntDirectorySize + len(self.tables) * sfntDirectoryEntrySize 2567842e56b97ce677b83bdab09cda48bc2d89ac75aJust assert directory_end == len(directory) 25791bca4244286fb519c93fe92329da96b0e6f32eejvr 25891bca4244286fb519c93fe92329da96b0e6f32eejvr checksums.append(calcChecksum(directory)) 25991bca4244286fb519c93fe92329da96b0e6f32eejvr checksum = sum(checksums) & 0xffffffff 2607842e56b97ce677b83bdab09cda48bc2d89ac75aJust # BiboAfba! 26191bca4244286fb519c93fe92329da96b0e6f32eejvr checksumadjustment = (0xB1B0AFBA - checksum) & 0xffffffff 26291bca4244286fb519c93fe92329da96b0e6f32eejvr return checksumadjustment 26391bca4244286fb519c93fe92329da96b0e6f32eejvr 26491bca4244286fb519c93fe92329da96b0e6f32eejvr def writeMasterChecksum(self, directory): 26591bca4244286fb519c93fe92329da96b0e6f32eejvr checksumadjustment = self._calcMasterChecksum(directory) 2667842e56b97ce677b83bdab09cda48bc2d89ac75aJust # write the checksum to the file 2677842e56b97ce677b83bdab09cda48bc2d89ac75aJust self.file.seek(self.tables['head'].offset + 8) 2680e2aecec53da493c44d6a5c253910a9475da218apabs self.file.write(struct.pack(">L", checksumadjustment)) 2691ebda677eb6061e809c422fc6d3b483f965a8281jvr 2707842e56b97ce677b83bdab09cda48bc2d89ac75aJust 2717842e56b97ce677b83bdab09cda48bc2d89ac75aJust# -- sfnt directory helpers and cruft 2727842e56b97ce677b83bdab09cda48bc2d89ac75aJust 2737e91e776c9d10d3b295de06ee7f665d8106306d8pabsttcHeaderFormat = """ 2747e91e776c9d10d3b295de06ee7f665d8106306d8pabs > # big endian 2757e91e776c9d10d3b295de06ee7f665d8106306d8pabs TTCTag: 4s # "ttcf" 2767e91e776c9d10d3b295de06ee7f665d8106306d8pabs Version: L # 0x00010000 or 0x00020000 2777e91e776c9d10d3b295de06ee7f665d8106306d8pabs numFonts: L # number of fonts 2787e91e776c9d10d3b295de06ee7f665d8106306d8pabs # OffsetTable[numFonts]: L # array with offsets from beginning of file 2797e91e776c9d10d3b295de06ee7f665d8106306d8pabs # ulDsigTag: L # version 2.0 only 2807e91e776c9d10d3b295de06ee7f665d8106306d8pabs # ulDsigLength: L # version 2.0 only 2817e91e776c9d10d3b295de06ee7f665d8106306d8pabs # ulDsigOffset: L # version 2.0 only 2827e91e776c9d10d3b295de06ee7f665d8106306d8pabs""" 2837e91e776c9d10d3b295de06ee7f665d8106306d8pabs 2847e91e776c9d10d3b295de06ee7f665d8106306d8pabsttcHeaderSize = sstruct.calcsize(ttcHeaderFormat) 2857e91e776c9d10d3b295de06ee7f665d8106306d8pabs 2867842e56b97ce677b83bdab09cda48bc2d89ac75aJustsfntDirectoryFormat = """ 2877842e56b97ce677b83bdab09cda48bc2d89ac75aJust > # big endian 288b0e5f299ffc5794f1960e694a855a05fc9cea01ejvr sfntVersion: 4s 289b0e5f299ffc5794f1960e694a855a05fc9cea01ejvr numTables: H # number of tables 290b0e5f299ffc5794f1960e694a855a05fc9cea01ejvr searchRange: H # (max2 <= numTables)*16 291b0e5f299ffc5794f1960e694a855a05fc9cea01ejvr entrySelector: H # log2(max2 <= numTables) 292b0e5f299ffc5794f1960e694a855a05fc9cea01ejvr rangeShift: H # numTables*16-searchRange 2937842e56b97ce677b83bdab09cda48bc2d89ac75aJust""" 2947842e56b97ce677b83bdab09cda48bc2d89ac75aJust 2957842e56b97ce677b83bdab09cda48bc2d89ac75aJustsfntDirectorySize = sstruct.calcsize(sfntDirectoryFormat) 2967842e56b97ce677b83bdab09cda48bc2d89ac75aJust 2977842e56b97ce677b83bdab09cda48bc2d89ac75aJustsfntDirectoryEntryFormat = """ 2987842e56b97ce677b83bdab09cda48bc2d89ac75aJust > # big endian 299b0e5f299ffc5794f1960e694a855a05fc9cea01ejvr tag: 4s 3000e2aecec53da493c44d6a5c253910a9475da218apabs checkSum: L 3010e2aecec53da493c44d6a5c253910a9475da218apabs offset: L 3020e2aecec53da493c44d6a5c253910a9475da218apabs length: L 3037842e56b97ce677b83bdab09cda48bc2d89ac75aJust""" 3047842e56b97ce677b83bdab09cda48bc2d89ac75aJust 3057842e56b97ce677b83bdab09cda48bc2d89ac75aJustsfntDirectoryEntrySize = sstruct.calcsize(sfntDirectoryEntryFormat) 3067842e56b97ce677b83bdab09cda48bc2d89ac75aJust 30758d7416124dc0ebaa3faccb1b77dd5f7926a628aBehdad EsfahbodwoffDirectoryFormat = """ 30858d7416124dc0ebaa3faccb1b77dd5f7926a628aBehdad Esfahbod > # big endian 30958d7416124dc0ebaa3faccb1b77dd5f7926a628aBehdad Esfahbod signature: 4s # "wOFF" 31058d7416124dc0ebaa3faccb1b77dd5f7926a628aBehdad Esfahbod sfntVersion: 4s 31158d7416124dc0ebaa3faccb1b77dd5f7926a628aBehdad Esfahbod length: L # total woff file size 31258d7416124dc0ebaa3faccb1b77dd5f7926a628aBehdad Esfahbod numTables: H # number of tables 31358d7416124dc0ebaa3faccb1b77dd5f7926a628aBehdad Esfahbod reserved: H # set to 0 31458d7416124dc0ebaa3faccb1b77dd5f7926a628aBehdad Esfahbod totalSfntSize: L # uncompressed size 31558d7416124dc0ebaa3faccb1b77dd5f7926a628aBehdad Esfahbod majorVersion: H # major version of WOFF file 31658d7416124dc0ebaa3faccb1b77dd5f7926a628aBehdad Esfahbod minorVersion: H # minor version of WOFF file 31758d7416124dc0ebaa3faccb1b77dd5f7926a628aBehdad Esfahbod metaOffset: L # offset to metadata block 31858d7416124dc0ebaa3faccb1b77dd5f7926a628aBehdad Esfahbod metaLength: L # length of compressed metadata 31958d7416124dc0ebaa3faccb1b77dd5f7926a628aBehdad Esfahbod metaOrigLength: L # length of uncompressed metadata 32058d7416124dc0ebaa3faccb1b77dd5f7926a628aBehdad Esfahbod privOffset: L # offset to private data block 32158d7416124dc0ebaa3faccb1b77dd5f7926a628aBehdad Esfahbod privLength: L # length of private data block 32258d7416124dc0ebaa3faccb1b77dd5f7926a628aBehdad Esfahbod""" 32358d7416124dc0ebaa3faccb1b77dd5f7926a628aBehdad Esfahbod 32458d7416124dc0ebaa3faccb1b77dd5f7926a628aBehdad EsfahbodwoffDirectorySize = sstruct.calcsize(woffDirectoryFormat) 32558d7416124dc0ebaa3faccb1b77dd5f7926a628aBehdad Esfahbod 32658d7416124dc0ebaa3faccb1b77dd5f7926a628aBehdad EsfahbodwoffDirectoryEntryFormat = """ 32758d7416124dc0ebaa3faccb1b77dd5f7926a628aBehdad Esfahbod > # big endian 32858d7416124dc0ebaa3faccb1b77dd5f7926a628aBehdad Esfahbod tag: 4s 32958d7416124dc0ebaa3faccb1b77dd5f7926a628aBehdad Esfahbod offset: L 33058d7416124dc0ebaa3faccb1b77dd5f7926a628aBehdad Esfahbod length: L # compressed length 33158d7416124dc0ebaa3faccb1b77dd5f7926a628aBehdad Esfahbod origLength: L # original length 332b0dc6dfc8baf01db94782fccc2e734a281b9ba12Behdad Esfahbod checkSum: L # original checksum 33358d7416124dc0ebaa3faccb1b77dd5f7926a628aBehdad Esfahbod""" 33458d7416124dc0ebaa3faccb1b77dd5f7926a628aBehdad Esfahbod 33558d7416124dc0ebaa3faccb1b77dd5f7926a628aBehdad EsfahbodwoffDirectoryEntrySize = sstruct.calcsize(woffDirectoryEntryFormat) 33658d7416124dc0ebaa3faccb1b77dd5f7926a628aBehdad Esfahbod 33758d7416124dc0ebaa3faccb1b77dd5f7926a628aBehdad Esfahbod 338e388db566b9ba42669c7e353db4293cf27bc2a5bBehdad Esfahbodclass DirectoryEntry(object): 3397842e56b97ce677b83bdab09cda48bc2d89ac75aJust 340b0dc6dfc8baf01db94782fccc2e734a281b9ba12Behdad Esfahbod def __init__(self): 341b0dc6dfc8baf01db94782fccc2e734a281b9ba12Behdad Esfahbod self.uncompressed = False # if True, always embed entry raw 342b0dc6dfc8baf01db94782fccc2e734a281b9ba12Behdad Esfahbod 343ea9dfa9fb28966175bf2275d20aeb62c3040c86djvr def fromFile(self, file): 34458d7416124dc0ebaa3faccb1b77dd5f7926a628aBehdad Esfahbod sstruct.unpack(self.format, file.read(self.formatSize), self) 3457842e56b97ce677b83bdab09cda48bc2d89ac75aJust 346ea9dfa9fb28966175bf2275d20aeb62c3040c86djvr def fromString(self, str): 34758d7416124dc0ebaa3faccb1b77dd5f7926a628aBehdad Esfahbod sstruct.unpack(self.format, str, self) 3487842e56b97ce677b83bdab09cda48bc2d89ac75aJust 349ea9dfa9fb28966175bf2275d20aeb62c3040c86djvr def toString(self): 35058d7416124dc0ebaa3faccb1b77dd5f7926a628aBehdad Esfahbod return sstruct.pack(self.format, self) 3517842e56b97ce677b83bdab09cda48bc2d89ac75aJust 3527842e56b97ce677b83bdab09cda48bc2d89ac75aJust def __repr__(self): 3537842e56b97ce677b83bdab09cda48bc2d89ac75aJust if hasattr(self, "tag"): 35458d7416124dc0ebaa3faccb1b77dd5f7926a628aBehdad Esfahbod return "<%s '%s' at %x>" % (self.__class__.__name__, self.tag, id(self)) 3557842e56b97ce677b83bdab09cda48bc2d89ac75aJust else: 35658d7416124dc0ebaa3faccb1b77dd5f7926a628aBehdad Esfahbod return "<%s at %x>" % (self.__class__.__name__, id(self)) 35758d7416124dc0ebaa3faccb1b77dd5f7926a628aBehdad Esfahbod 35858d7416124dc0ebaa3faccb1b77dd5f7926a628aBehdad Esfahbod def loadData(self, file): 35958d7416124dc0ebaa3faccb1b77dd5f7926a628aBehdad Esfahbod file.seek(self.offset) 36058d7416124dc0ebaa3faccb1b77dd5f7926a628aBehdad Esfahbod data = file.read(self.length) 36158d7416124dc0ebaa3faccb1b77dd5f7926a628aBehdad Esfahbod assert len(data) == self.length 362b0dc6dfc8baf01db94782fccc2e734a281b9ba12Behdad Esfahbod if hasattr(self.__class__, 'decodeData'): 363b0dc6dfc8baf01db94782fccc2e734a281b9ba12Behdad Esfahbod data = self.decodeData(data) 364b0dc6dfc8baf01db94782fccc2e734a281b9ba12Behdad Esfahbod return data 365b0dc6dfc8baf01db94782fccc2e734a281b9ba12Behdad Esfahbod 366b0dc6dfc8baf01db94782fccc2e734a281b9ba12Behdad Esfahbod def saveData(self, file, data): 367b0dc6dfc8baf01db94782fccc2e734a281b9ba12Behdad Esfahbod if hasattr(self.__class__, 'encodeData'): 368b0dc6dfc8baf01db94782fccc2e734a281b9ba12Behdad Esfahbod data = self.encodeData(data) 369b0dc6dfc8baf01db94782fccc2e734a281b9ba12Behdad Esfahbod self.length = len(data) 370b0dc6dfc8baf01db94782fccc2e734a281b9ba12Behdad Esfahbod file.seek(self.offset) 371b0dc6dfc8baf01db94782fccc2e734a281b9ba12Behdad Esfahbod file.write(data) 37258d7416124dc0ebaa3faccb1b77dd5f7926a628aBehdad Esfahbod 37358d7416124dc0ebaa3faccb1b77dd5f7926a628aBehdad Esfahbod def decodeData(self, rawData): 37458d7416124dc0ebaa3faccb1b77dd5f7926a628aBehdad Esfahbod return rawData 37558d7416124dc0ebaa3faccb1b77dd5f7926a628aBehdad Esfahbod 376b0dc6dfc8baf01db94782fccc2e734a281b9ba12Behdad Esfahbod def encodeData(self, data): 377b0dc6dfc8baf01db94782fccc2e734a281b9ba12Behdad Esfahbod return data 378b0dc6dfc8baf01db94782fccc2e734a281b9ba12Behdad Esfahbod 37958d7416124dc0ebaa3faccb1b77dd5f7926a628aBehdad Esfahbodclass SFNTDirectoryEntry(DirectoryEntry): 38058d7416124dc0ebaa3faccb1b77dd5f7926a628aBehdad Esfahbod 38158d7416124dc0ebaa3faccb1b77dd5f7926a628aBehdad Esfahbod format = sfntDirectoryEntryFormat 38258d7416124dc0ebaa3faccb1b77dd5f7926a628aBehdad Esfahbod formatSize = sfntDirectoryEntrySize 38358d7416124dc0ebaa3faccb1b77dd5f7926a628aBehdad Esfahbod 38458d7416124dc0ebaa3faccb1b77dd5f7926a628aBehdad Esfahbodclass WOFFDirectoryEntry(DirectoryEntry): 38558d7416124dc0ebaa3faccb1b77dd5f7926a628aBehdad Esfahbod 38658d7416124dc0ebaa3faccb1b77dd5f7926a628aBehdad Esfahbod format = woffDirectoryEntryFormat 38758d7416124dc0ebaa3faccb1b77dd5f7926a628aBehdad Esfahbod formatSize = woffDirectoryEntrySize 388b0dc6dfc8baf01db94782fccc2e734a281b9ba12Behdad Esfahbod zlibCompressionLevel = 6 38958d7416124dc0ebaa3faccb1b77dd5f7926a628aBehdad Esfahbod 39058d7416124dc0ebaa3faccb1b77dd5f7926a628aBehdad Esfahbod def decodeData(self, rawData): 39158d7416124dc0ebaa3faccb1b77dd5f7926a628aBehdad Esfahbod import zlib 39258d7416124dc0ebaa3faccb1b77dd5f7926a628aBehdad Esfahbod if self.length == self.origLength: 39358d7416124dc0ebaa3faccb1b77dd5f7926a628aBehdad Esfahbod data = rawData 39458d7416124dc0ebaa3faccb1b77dd5f7926a628aBehdad Esfahbod else: 39558d7416124dc0ebaa3faccb1b77dd5f7926a628aBehdad Esfahbod assert self.length < self.origLength 39658d7416124dc0ebaa3faccb1b77dd5f7926a628aBehdad Esfahbod data = zlib.decompress(rawData) 39758d7416124dc0ebaa3faccb1b77dd5f7926a628aBehdad Esfahbod assert len (data) == self.origLength 39858d7416124dc0ebaa3faccb1b77dd5f7926a628aBehdad Esfahbod return data 39958d7416124dc0ebaa3faccb1b77dd5f7926a628aBehdad Esfahbod 400b0dc6dfc8baf01db94782fccc2e734a281b9ba12Behdad Esfahbod def encodeData(self, data): 401b0dc6dfc8baf01db94782fccc2e734a281b9ba12Behdad Esfahbod import zlib 402b0dc6dfc8baf01db94782fccc2e734a281b9ba12Behdad Esfahbod self.origLength = len(data) 403b0dc6dfc8baf01db94782fccc2e734a281b9ba12Behdad Esfahbod if not self.uncompressed: 404b0dc6dfc8baf01db94782fccc2e734a281b9ba12Behdad Esfahbod compressedData = zlib.compress(data, self.zlibCompressionLevel) 405b0dc6dfc8baf01db94782fccc2e734a281b9ba12Behdad Esfahbod if self.uncompressed or len(compressedData) >= self.origLength: 406b0dc6dfc8baf01db94782fccc2e734a281b9ba12Behdad Esfahbod # Encode uncompressed 407b0dc6dfc8baf01db94782fccc2e734a281b9ba12Behdad Esfahbod rawData = data 408b0dc6dfc8baf01db94782fccc2e734a281b9ba12Behdad Esfahbod self.length = self.origLength 409b0dc6dfc8baf01db94782fccc2e734a281b9ba12Behdad Esfahbod else: 410b0dc6dfc8baf01db94782fccc2e734a281b9ba12Behdad Esfahbod rawData = compressedData 411b0dc6dfc8baf01db94782fccc2e734a281b9ba12Behdad Esfahbod self.length = len(rawData) 412b0dc6dfc8baf01db94782fccc2e734a281b9ba12Behdad Esfahbod return rawData 413b0dc6dfc8baf01db94782fccc2e734a281b9ba12Behdad Esfahbod 41458d7416124dc0ebaa3faccb1b77dd5f7926a628aBehdad Esfahbodclass WOFFFlavorData(): 41558d7416124dc0ebaa3faccb1b77dd5f7926a628aBehdad Esfahbod 416b0dc6dfc8baf01db94782fccc2e734a281b9ba12Behdad Esfahbod Flavor = 'woff' 417b0dc6dfc8baf01db94782fccc2e734a281b9ba12Behdad Esfahbod 41858d7416124dc0ebaa3faccb1b77dd5f7926a628aBehdad Esfahbod def __init__(self, reader=None): 41958d7416124dc0ebaa3faccb1b77dd5f7926a628aBehdad Esfahbod self.majorVersion = None 42058d7416124dc0ebaa3faccb1b77dd5f7926a628aBehdad Esfahbod self.minorVersion = None 42158d7416124dc0ebaa3faccb1b77dd5f7926a628aBehdad Esfahbod self.metaData = None 42258d7416124dc0ebaa3faccb1b77dd5f7926a628aBehdad Esfahbod self.privData = None 42358d7416124dc0ebaa3faccb1b77dd5f7926a628aBehdad Esfahbod if reader: 42458d7416124dc0ebaa3faccb1b77dd5f7926a628aBehdad Esfahbod self.majorVersion = reader.majorVersion 42558d7416124dc0ebaa3faccb1b77dd5f7926a628aBehdad Esfahbod self.minorVersion = reader.minorVersion 42658d7416124dc0ebaa3faccb1b77dd5f7926a628aBehdad Esfahbod if reader.metaLength: 42758d7416124dc0ebaa3faccb1b77dd5f7926a628aBehdad Esfahbod reader.file.seek(reader.metaOffset) 428153ec402094adbea673e914385b87f1d99191d0bBehdad Esfahbod rawData = reader.file.read(reader.metaLength) 42958d7416124dc0ebaa3faccb1b77dd5f7926a628aBehdad Esfahbod assert len(rawData) == reader.metaLength 430153ec402094adbea673e914385b87f1d99191d0bBehdad Esfahbod import zlib 43158d7416124dc0ebaa3faccb1b77dd5f7926a628aBehdad Esfahbod data = zlib.decompress(rawData) 43258d7416124dc0ebaa3faccb1b77dd5f7926a628aBehdad Esfahbod assert len(data) == reader.metaOrigLength 43358d7416124dc0ebaa3faccb1b77dd5f7926a628aBehdad Esfahbod self.metaData = data 43458d7416124dc0ebaa3faccb1b77dd5f7926a628aBehdad Esfahbod if reader.privLength: 43558d7416124dc0ebaa3faccb1b77dd5f7926a628aBehdad Esfahbod reader.file.seek(reader.privOffset) 436153ec402094adbea673e914385b87f1d99191d0bBehdad Esfahbod data = reader.file.read(reader.privLength) 43758d7416124dc0ebaa3faccb1b77dd5f7926a628aBehdad Esfahbod assert len(data) == reader.privLength 43858d7416124dc0ebaa3faccb1b77dd5f7926a628aBehdad Esfahbod self.privData = data 4397842e56b97ce677b83bdab09cda48bc2d89ac75aJust 4407842e56b97ce677b83bdab09cda48bc2d89ac75aJust 44191bca4244286fb519c93fe92329da96b0e6f32eejvrdef calcChecksum(data): 4427842e56b97ce677b83bdab09cda48bc2d89ac75aJust """Calculate the checksum for an arbitrary block of data. 4437842e56b97ce677b83bdab09cda48bc2d89ac75aJust Optionally takes a 'start' argument, which allows you to 4447842e56b97ce677b83bdab09cda48bc2d89ac75aJust calculate a checksum in chunks by feeding it a previous 4457842e56b97ce677b83bdab09cda48bc2d89ac75aJust result. 4467842e56b97ce677b83bdab09cda48bc2d89ac75aJust 4477842e56b97ce677b83bdab09cda48bc2d89ac75aJust If the data length is not a multiple of four, it assumes 4487842e56b97ce677b83bdab09cda48bc2d89ac75aJust it is to be padded with null byte. 44991bca4244286fb519c93fe92329da96b0e6f32eejvr 450821572c9a92d338a7ecbb4261c08ce378eb5434dBehdad Esfahbod >>> print calcChecksum(b"abcd") 45191bca4244286fb519c93fe92329da96b0e6f32eejvr 1633837924 452821572c9a92d338a7ecbb4261c08ce378eb5434dBehdad Esfahbod >>> print calcChecksum(b"abcdxyz") 45391bca4244286fb519c93fe92329da96b0e6f32eejvr 3655064932 4547842e56b97ce677b83bdab09cda48bc2d89ac75aJust """ 4557842e56b97ce677b83bdab09cda48bc2d89ac75aJust remainder = len(data) % 4 4567842e56b97ce677b83bdab09cda48bc2d89ac75aJust if remainder: 457821572c9a92d338a7ecbb4261c08ce378eb5434dBehdad Esfahbod data += b"\0" * (4 - remainder) 45891bca4244286fb519c93fe92329da96b0e6f32eejvr value = 0 45991bca4244286fb519c93fe92329da96b0e6f32eejvr blockSize = 4096 46091bca4244286fb519c93fe92329da96b0e6f32eejvr assert blockSize % 4 == 0 46197dea0a5d02ba1655d27a06fe91540e3495b8ef9Behdad Esfahbod for i in range(0, len(data), blockSize): 46291bca4244286fb519c93fe92329da96b0e6f32eejvr block = data[i:i+blockSize] 46391bca4244286fb519c93fe92329da96b0e6f32eejvr longs = struct.unpack(">%dL" % (len(block) // 4), block) 46491bca4244286fb519c93fe92329da96b0e6f32eejvr value = (value + sum(longs)) & 0xffffffff 46591bca4244286fb519c93fe92329da96b0e6f32eejvr return value 4667842e56b97ce677b83bdab09cda48bc2d89ac75aJust 4677842e56b97ce677b83bdab09cda48bc2d89ac75aJust 46891bca4244286fb519c93fe92329da96b0e6f32eejvrif __name__ == "__main__": 46991bca4244286fb519c93fe92329da96b0e6f32eejvr import doctest 47091bca4244286fb519c93fe92329da96b0e6f32eejvr doctest.testmod() 471